21937193191 has 2 divisors, whose sum is σ = 21937193192. Its totient is φ = 21937193190.

The previous prime is 21937193171. The next prime is 21937193209. The reversal of 21937193191 is 19139173912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21937193191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21937193101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10968596595 + 10968596596.

It is an arithmetic number, because the mean of its divisors is an integer number (10968596596).

Almost surely, 2^21937193191 is an apocalyptic number.

21937193191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21937193191 is an equidigital number, since it uses as much as digits as its factorization.

21937193191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 91854, while the sum is 46.

The spelling of 21937193191 in words is "twenty-one billion, nine hundred thirty-seven million, one hundred ninety-three thousand, one hundred ninety-one".